Conventional recovery and formulation methods relating to proteins produced by microbial fermentation involve several processing steps (e.g., Enzymes in Industry: Production and Applications (2007) Wolfgang Aehle, ed., 3rd edition, Wiley-VCH, p. 49; Bioseparations: Science and Engineering (2003) R. G. Harrison et al., Oxford University Press, p. 32). Any one of a number of solid-liquid separation methods can be employed to produce a clarified solution containing the protein of interest.
Depending on the desired final product concentration and purity, this clarified liquid containing the protein of interest may meet the requirements for formulation to produce the product. Other times, further processing is required to increase the concentration and/or purity of the protein prior to formulation. Concentration involves dewatering, which, for heat sensitive proteins, is typically achieved by ultrafiltration.